Centrifugal pump formed by pressing and welding and its manufacturing process

Abstract

The invention relates to a centrifugal pump and it's manufacturing process, more particularly to a pump formed by pressing and welding metal sheet. In this invention, comprising a pump casing, an impeller, labyrinth ring supports, labyrinth rings, a real cover and a chassis, characterized in that the manufacturing process of said pump casing includes following steps: using a female mold made by wear-resisting metal, the female space in said female mold is a near 360° integrated spiral with radial expanded gradually shape and approximately semicircle cross section, using a male mold made by pressing deformable soft or elastic material, putting a tubular member with flange made by metal sheet between said molds, closing said molds, expanding said male mold made by soft or elastic material. Said tubular member will be expanded into a near 360° integrated spiral casing with radial expanded gradually shape and approximately semicircle cross section.

What is claimed is:  
     
       1. A centrifugal pump formed by pressing and welding, consisting of an entrance flange, a discharge flange, a rear cover, a pump casing, and an impeller, characterized in that in the pump casing there is an integrated spiral chamber of approximately 360° pressed between the pump casing and the impeller, the chamber gradually increasing radially outward in the flowing direction of the fluid, its cross section being roughly a semicircle, there also being a discharge aperture roughly shaped as an ellipse, the discharge aperture neck being connected to the discharge aperture of the pump casing, the discharge aperture neck of the pump casing is welded on the discharge aperture of the pump casing with a diametrically-variable ellipse shape, the axial outer surface at the joint of the pump casing and the entrance flange is a camber with a gradually varying curvature, the curvature of the axial outer surface of the pump casing varies in connection with the radially extending height, the larger the radial extension, the smaller the axial curvature, in the pump casing there is labyrinth ring supports, which connect and support the inner side and outer side of the place where both the ribs of the entrance flange and the labyrinth ring supports sustain the pump casing. 
     
     
       2. A centrifugal pump formed by pressing and welding according to  claim 1 , characterized in that at least two evenly distributed ribs join the pump casing to the entrance flange. 
     
     
       3. A centrifugal pump formed by pressing and welding according to  claim 1 , characterized in that said impeller consists of a front impeller plate, a rear impeller plate and a spiral impeller blade sandwiched between said two plates. 
     
     
       4. A centrifugal pump formed by pressing and welding according to  claim 1 , characterized in that between the entrance of the impeller and the pump casing there are labyrinth rings located in the labyrinth ring supports for the purpose of sealing. 
     
     
       5. A manufacturing process of a centrifugal pump formed by pressing and welding, by which the pump casing, the impeller, the labyrinth supports, the labyrinth rings, the rear cover and the chassis are formed by pressing, characterized in that the manufacturing process of the pump casing is as follows: an openable female mold is made of wear-resistant metal, the inside of the female mold takes an integrated spiral shape of approximately 360°, its cross section resembles roughly a semicircle that gradually increases radially outward, the internal male mold is made of pressing-deformable flexible or elastic material, the metal sheets are pressed into a tubular unit with flange, which will be inserted between the molds, then the molds will be closed and the male mold made of the flexible or elastic material will expand so that the tubular unit will expand in the radial direction into a gradually increasing integrated spiral case of approximately 360°, whose cross section resembles roughly a semicircle. 
     
     
       6. The manufacturing process of a centrifugal pump formed by pressing and welding according to  claim 5 , characterized in that the flexible and elastic material made into the internal mold is polyurethane rubber.